A flow-tube based laser-induced fluorescence instrument to measure OH reactivity in the troposphere
- 1School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
- 2Department of Chemistry, University of York, York, YO10 5DD, UK
- 3National Centre for Atmospheric Science (NCAS), University of Leeds, Leeds, LS2 9JT, UK
- 4National Centre for Atmospheric Science (NCAS), University of York, York, YO10 5DD, UK
- †deceased, 28 July 2009
Abstract. A field instrument utilising the artificial generation of OH radicals in a sliding injector flow-tube reactor with detection by laser-induced fluorescence spectroscopy has been developed to measure the rate of decay of OH by reaction with its atmospheric sinks. The OH reactivity instrument has been calibrated using known concentrations of CO, NO2 and single hydrocarbons in a flow of zero air, and the impact of recycling of OH via the reaction HO2+NO→OH+NO2 on the measured OH reactivity has been quantified. As well as a detailed description of the apparatus, the capabilities of the new instrument are illustrated using representative results from deployment in the semi-polluted marine boundary layer at the Weybourne Atmospheric Observatory, UK, and in a tropical rainforest at the Bukit Atur Global Atmospheric Watch station, Danum Valley, Borneo.